Advisories were originally intended to be helpful, but are now abused and can even be of no value.
When we moved to here I had no idea where to take our previous van for it's Mot and plucked one out of the air. They passed it, but gave us a batch of advisories.
I ignored the lot and took the van to a place recommended as being fair, and showed them the previous ignored advisories. They smiled, and passed it it without issue.
Obviously, they couldn't confirm that it was a scam aimed at drumming up work, but in my view that's exactly what it was.